Commitments and Contingencies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended		1 Months Ended
	Sep. 30, 2012	Sep. 30, 2012 Land Improvements	Jun. 30, 2006 Lease Agreements	Jun. 30, 2008 First Amendment	Dec. 31, 2010 Second Amendment
Commitments and Contingencies [Line Items]
Commitment to lease property, total lease consideration for the assignment would be received by anchor tenant	$ 2,550
Commitment to lease property, lease consideration remitted to anchor tenant by ARJAX , to date	1,400
Obligation for repairs or improvements		500
Effective date			February 2009	January 31, 2011	February 28, 2014
Capital commitments obligation of NPAMLP	$ 67